Note: Not all dendritic spines are visualized in the examples of confocal microscopy images since those spines that protrude from the front and back of the dendrites are masked (they can be visualized in the 3D reconstructions).
Thus, the number of musical notes is higher than the number of spines observed in the figures. The insertion point has been selected for fixing the spatial position of the spines because it is more stable than other options.